# Plotting problem for a series of plots [closed]

    g[x_] = 5.91167 +
x (8.63312*10^-10 +
x (0.0020623 +
x (1.35313*10^-9 +
x (-2.80417*10^-6 +
x (4.03869*10^-10 +
x (5.32053*10^-9 +
x (3.67271*10^-11 +
x (-1.98534*10^-11 +
x (1.21118*10^-12 +
x (-1.22954*10^-13 +
x (1.50555*10^-14 +
x (-1.21169*10^-15 +
x (6.31704*10^-17 +
x (-2.18852*10^-18 +
x (4.90556*10^-20 +
x (-6.17301*10^-22 +
x (1.52676*10^-24 + (6.42075*10^-26 -
6.38913*10^-28 x) x)))))))))))))))));

u[x_] = 8.07314 +
x (-2.324*10^-10 +
x (9.86155*10^-6 +
x (-3.25595*10^-10 +
x (1.59488*10^-10 +
x (-8.488*10^-11 +
x (2.72002*10^-11 +
x (-6.65937*10^-12 +
x (1.26859*10^-12 +
x (-1.90257*10^-13 +
x (2.26144*10^-14 +
x (-2.1351*10^-15 +
x (1.5977*10^-16 +
x (-9.4094*10^-18 +
x (4.30444*10^-19 +
x (-1.4968*10^-20 +
x (3.82*10^-22 +
x (-6.7422*10^-24 + (7.34849*10^-26 -
3.72468*10^-28 x) x)))))))))))))))));

d[x_] = 7.38802 +
x (-8.88743*10^-8 +
x (0.00266487 +
x (-1.27894*10^-7 +
x (-7.27354*10^-6 +
x (-3.40462*10^-8 +
x (3.8489*10^-8 +
x (-2.65374*10^-9 +
x (3.75549*10^-10 +
x (-6.98473*10^-11 +
x (8.02382*10^-12 +
x (-5.90205*10^-13 +
x (2.93816*10^-14 +
x (-1.00062*10^-15 +
x (2.25617*10^-17 + (-3.05627*10^-19 +
1.89199*10^-21 x) x))))))))))))));

b[x_] = 6.69883 +
x (6.60446*10^-10 +
x (0.0000768412 +
x (8.98369*10^-10 +
x (-6.10391*10^-9 +
x (2.26188*10^-10 +
x (-7.06931*10^-11 +
x (1.7111*10^-11 +
x (-3.20167*10^-12 +
x (4.71874*10^-13 +
x (-5.51587*10^-14 +
x (5.1257*10^-15 +
x (-3.77865*10^-16 +
x (2.19445*10^-17 +
x (-9.90901*10^-19 +
x (3.40446*10^-20 +
x (-8.5928*10^-22 +
x (1.50126*10^-23 + (-1.62111*10^-25 +
8.14743*10^-28 x) x)))))))))))))))));

p1 = Plot[b[x], {x, 0, 10}, PlotLegends -> {"Black Sea"}];
p2 = Plot[d[x], {x, 0, 10}, PlotLegends -> {"Draupner"}];
p3 = Plot[g[x], {x, 0, 10}, PlotLegends -> {"Gorm"}];
p4 = Plot[u[x], {x, 0, 10}, PlotLegends -> {"Ucluelet"}];

Show[p1, p2, p3, p4]


Is it possible that these functions, which are so dissimilar, are equal?

The plot shows only one plot.

They are different:

Plot[{g[x], u[x], d[x], b[x]}, {x, 0, 50}]


You can see this also analytically by e.g.:

g[x] - u[x] // Chop // Simplify


Just change your last Showcommand to

Show[{p1, p2, p3, p4}, PlotRange -> All]